1. Field of the Invention
The present invention relates to an inverter device including a plurality of switching elements that convert electric power between DC power and AC power, a base plate that includes an element placing surface on which these plurality of switching elements are placed, AC terminals through which AC power is input and output to and from an external device and which are electrically connected to the switching elements, and a capacitor that smoothes DC power.
2. Description of the Related Art
In recent years, a hybrid vehicle or an electric vehicle, which includes a rotary electric machine as a driving power source, has come into the spotlight in terms of energy saving or the reduction of environmental burden. There are many cases where a DC power source such as a high-voltage battery is generally provided and the rotary electric machine is driven by AC power in the hybrid vehicle or the like. For this reason, the hybrid vehicle or the like is provided with an inverter device between the DC power source and the rotary electric machine. Meanwhile, the inverter device is not limited to the use for a hybrid vehicle or the like, and may generally be required even for air conditioning equipment, electric power controllers, or the like.
A device disclosed in, for example, the following JP-A-2008-29094 has already been known as the above-mentioned inverter device. Hereinafter, names and reference numerals of corresponding members disclosed in JP-A-2008-29094 will be quoted in square brackets in the description of the section of the background art. As shown in FIGS. 2 and 3 of JP-A-2008-29094, this device includes a base plate [motor substrate 120 and cooling fins 12] on which a plurality of switching elements [MOS-FETs 111a to 111f] are provided, AC terminals [AC terminals 71, 72, and 73] through which AC power is input and output to and from an external device [motor generator 940], and capacitors [electrolytic capacitors 21, 22, and 23] that smooth DC power. In this device, the capacitors, the base plate, and the AC terminals are sequentially arrayed in a predetermined direction (a vertical direction in FIG. 3 of JP-A-2008-29094) in plan view seen in a direction perpendicular to an element placing surface on which the plurality of switching elements are placed. Further, the AC terminals are disposed so as to protrude from a case [housing 10], which receives the capacitors and the base plate, in the predetermined direction. Meanwhile, one (positive electrode-secondary DC terminal 61) of the power supply terminals, through which DC power is input and output to and from a DC power source, is also disposed so as to protrude from the case in the predetermined direction.
It is preferable that the entire size of the inverter device be generally reduced as much as possible when the inverter device is formed. In particular, since there is a limitation on the mounting of the inverter device on a vehicle in the use for a hybrid vehicle or the like, the above-mentioned request is particularly significant. In this respect, dead spaces are formed between the AC terminals and the power supply terminal, which protrude from the case in the predetermined direction, in the device of JP-A-2008-29094. As a result, there has been a problem in that the entire size of the inverter device is increased. Further, since the capacitors significantly protrude from the base plate in the direction perpendicular to the element placing surface as shown in FIG. 5 of JP-A-2008-29094 in the device of JP-A-2008-29094, the entire size of the inverter device has been increased due to this aspect.